The 4 bolts are at the immediate front and rear of each rail. They are 10 mm bolts. Move the seat all the way to the front and you will see the ones in the rear, which do not have plastic covers. The ones in the front look just like the ones in the back although they may have plastic covers, in which case you'll have to pry them off. I don't pay much attention to saving the covers - just throw them away. With a future classic you may want to be more careful. Replacements are available from the dealer.